New observations of lensed quasars show the Universe is expanding faster than expected. But these results raise questions about the assumptions of our cosmological models.
The Constant Of Time
The rate of cosmic expansion has changed over time. So why does it look like a constantly expanding universe?
New Evidence Challenges Rate Of Cosmic Expansion
A new measurements for the Hubble parameter raises interesting questions, but whether it leads to a new understanding of cosmic expansion and dark energy is yet to be seen.
Traveling Without Moving
With all the news about BICEP2 and the possible detection of early inflation, there have been a lot of misconceptions about what inflation actually is. One of the biggest is the idea that during inflation the universe expanded faster than light. It’s a misconception that even many experts get wrong.
Go With the Flow
When measuring the motion of distant galaxies, we use the Doppler effect to measure their speed relative to us. Basically, as a galaxy moves away from us, the light from the galaxy appears more red than it actually is. This is similar to the way the sound of a train can sound lower as it moves away from you. Of …
Push Me, Pull You
If the universe is expanding, how is it possible that galaxies can collide with each other? It turns out that not only are colliding galaxies possible in an expanding universe, the fact that they occur is due in part to dark matter and dark energy.
Bend and Stretch
Since space itself is expanding, the wavelength of the traveling light also stretches. This means that while the light travels, it continues to redshift due to cosmic expansion.
Ripples on the Cosmic Pond
The amazing thing is that all these values fit in this single curve. If the values were different the peaks would shift left or right, or be higher or lower. While the image of the CMB is wonderful, with its swirls of color, this graph is even more wonderful. It tells us that our understanding of the universe is on track.
Cosmic Energy
We know the universe is expanding at an ever increasing speed. This is due to a type of energy known as dark energy.
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